Graduate School of Pharmaceutical Sciences, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
J Pharm Sci. 2010 Oct;99(10):4192-200. doi: 10.1002/jps.22133.
A novel complex of salicylic acid (SA) and gamma-cyclodextrin (gamma-CD) was obtained via the sealed-heating method. The influence of the water content of gamma-CD on the complex formation with SA by sealed-heating process was investigated. Quantitative determination of SA revealed that sealed-heated samples of SA and gamma-CD with low water content (0.8-5.4%) formed the SA/gamma-CD = 2:1 complex, while the samples with high water content (8.5-11.5%) formed the SA/gamma-CD = 4:1 complex. The molecular arrangements of gamma-CD in 2:1 and 4:1 complexes were determined by powder X-ray diffraction measurements to be in monoclinic-columnar and tetragonal-columnar forms, respectively. The results of infrared spectroscopy and (13)C solid-state NMR measurements showed that two types of SA molecules resided in the 4:1 complex, whereas only one type of SA molecules existed in the 2:1 complex. The obtained 2:1 complex was assumed to contain two SA molecules per one gamma-CD, with the SA molecules existing in the intermolecular spaces formed by the gamma-CD columns. In the case of the 4:1 complex, two SA molecules were incorporated into the intermolecular spaces while the other two SA molecules were included within the gamma-CD cavity.
通过密封加热法获得了水杨酸（SA）和γ-环糊精（γ-CD）的新型配合物。研究了γ-CD 的含水量对密封加热过程中与 SA 形成配合物的影响。定量测定 SA 表明，低含水量（0.8-5.4%）的 SA 和 γ-CD 的密封加热样品形成了 SA/γ-CD=2:1 配合物，而高含水量（8.5-11.5%）的样品形成了 SA/γ-CD=4:1 配合物。通过粉末 X 射线衍射测量确定了 2:1 和 4:1 配合物中 γ-CD 的分子排列分别为单斜柱状和四方柱状。红外光谱和（13）C 固态 NMR 测量的结果表明，两种类型的 SA 分子存在于 4:1 配合物中，而在 2:1 配合物中仅存在一种类型的 SA 分子。所得到的 2:1 配合物被假定为每个γ-CD 包含两个 SA 分子，其中 SA 分子存在于γ-CD 柱形成的分子间空间中。在 4:1 配合物的情况下，两个 SA 分子被掺入分子间空间，而另外两个 SA 分子被包含在γ-CD 空腔内。
